Field of the Invention
This invention relates to underwater transmitting apparatus and, more particularly, to a hand-held underwater apparatus for transmitting an audible alarm signal.
Description of the Prior Art
U.S. Pat. No. 3,267,414 (Kritz) discloses portable underwater communications unit capable of voice or code transmission between free divers or between a diver and a vessel. The apparatus utilizes both transmitting and receiving apparatus for voice modulated, ultrasonic acoustic signal and sonar apparatus for code signals.
U.S. Pat. No. 3,337,841 (Wainwright et al) discloses underwater communications apparatus for providing voice communication between underwater swimmers. The apparatus is, essentially, underwater telephone apparatus which includes both transmitting and receiving elements.
U.S. Pat. No. 3,469,231 (Geiling et al) discloses communicating apparatus for communications between free swimming divers. The apparatus includes transducers transmitting and receiving ultrasonic frequencies.
U.S. Pat. No. 3,686,656 (Richards) discloses an automatic sound generating apparatus which generates a sound under water when a pressure responsive switch is closed to connect sound generating apparatus to an electrical current source. The apparatus is self-contained, and it is designed to be placed in a vessel so that if the vessel sinks, the apparatus will automatically transmit sound to help in locating and recovering the vessel.
U.S. Pat. No. 3,986,161 (MacKellar) discloses underwater directional guidance apparatus which utilizes a transducer within a housing and the transducer is activated through switches which are magnetically activated. A ring or collar disposed about the circular housing in which the transducer and its electrical components, including a battery, are housed, is rotatable. A magnet secured to the collar actuates switch elements when the magnet is brought into proximity of the switch elements.
U.S. Pat. No. 4,095,667 (Mahig et al) discloses portable underwater signaling apparatus which utilizes compressed air to drive a hammer against a diaphragm to generate sound waves transmitted through the water.
U.S. Pat. No. 4,281,404 (Morrow, Jr. et al) discloses a hand-held, self-contained depth finding apparatus. The apparatus is in the general configura-tion of a pistol, with the "barrel" of the pistol providing directional control for both sending and receiving sonic pulses for determining the depth of water.
U.S. Pat. No. 4,635,242 (Hart) discloses portable self-contained underwater signaling device utilized by a diver to transmit different types of signals. A three position switch is used to control the output of the signal generator. The switch includes an off or open position, a momentary on position, and a full on position. The output from the apparatus is different in the various positions.
The apparatus of the present invention differs from the above disclosed patents in several regards. For one thing, the apparatus of the present invention is much simpler to operate. Moreover, the apparatus of the present invention is designed to get the attention of other divers, and accordingly is limited in its acoustic output.